For many years, manufacturers and producers of such products as biscuits and cookies have had only several choices in the nature of package in which their product might be priced for retail sale. Such choices have included biscuit boxes -- usually of sheet steel and the like -- which, because of their cost, are only used for premium quality products which are sold at very high prices; as well as the more ordinary cardboard boxes and bags. In the latter category, the bags are usually laminated paper bags, where the interior laminates are of a plastic or paper material which is generally impervious to moisture, and the outer laminates are such that they may be printed upon for purposes of designating the product being sold in that package, its ingredients, etc.
Needless to say, any such package as is used by the manufacturer or producer of products such as biscuits and the like must be such that the product can be placed in the package by the manufacturer at his plant, in such a manner that the products are thereby sealed in a sanitary fashion sufficient to meet the requirements of Health Authorities and other Government and regulatory bodies; as well as to meet the rigours of crating, shipping, being placed on retail shelves, etc. Also, of course, the manufacturer is anxious to keep his packaging costs as low as possible in order that the highest reasonable portion of the consumers' money goes towards purchase of the product, and not of the package.
When consideration is made of the usual kind of bag in which biscuits, cookies and the like are sold to the retail market -- other than single laminate plastic bags -- it will be noted that such bags are sealed by a sealing strip which is placed across the top edge of the front or back panel of the bag in such a manner that when the top edges of the front and back panels of the bag are brought together and several folds made in them for purposes of sealing the bag, the strip extends laterally beyond the sides of the bag in such a manner that it may be then folded downwardly at each side of the bag so as to engage a crease formed between the front or back panel and the side panel of the bag at each side. In the usual circumstances, a thin ribbon or wire of metal -- usually steel -- is embedded in the sealing strip which is attached at the top edge of the front or rear panel of the bag, in order to provide the ability for the strip to be bent or folded into engagement with the front/side or back/side crease.
As the cost of steel increases, the cost of the sealing strip for such bags has also increased, thereby driving up the packaging costs for products to be sold in such bags. Also, it has been necessary to provide very complicated apparatus for creating the fold at each end of the sealing strip and to assure that the sealing strip engaged the appropriate crease in order to ensure that the package itself was properly sealed; or, in some operations, to employ hand labour.
Recently, a bag closure for such bags at those discussed above, where at least the front, back and side panels of the bag are pliable, has been developed. That closure is applied to one of the front or back panels of the bag -- for purposes of further discussion, it will be assumed that it is the front panel of the bag to which the closure is applied -- and has at least one tab portion formed therein which presents a hook-like pre-formed open jaw into which the folded top of the bag, when shut, may be inserted. In its usual embodiment, the closure just described has two pre-formed jaws, and is formed from sheet plastics material such as ABS or styrene.
One difficulty which has arisen, however, with the newly developed closure referred to above is that apparatus for applying that closure to a bag having product in it, without causing localized heating or crushing pressure against the product within the bag, has not previously been available. It was perceived, however, that if the bag having product in it were to be closed and folded in substantially the normal manner as employed in apparatus presently installed in most manufacturing facilities for production of packaged biscuits and the like, it would then be possible to apply a closure such as that discussed above over the folded end of the bag which would be intended to be inserted in the closure when the bag is being used by the consumer, and thereafter to apply a suitable adhesive to the closure and to fold over the folded top end of the bag so that the closure is applied to the front surface of the bag -- usually at the shoulder formed therein during the folding operation so as to be above the product within the bag, and maintained in such a position while the adhesive bond between the closure and front panel of the bag at least partially sets up. The bag would then be sealed and closed, and ready for packaging, shipment and retail sale in the usual manner.
Thus, this invention provides an apparatus for applying closures to bags and like containers, where the closure is as discussed above, consisting of conveyor means for feeding a plurality of bags or the like, seriatim, past a plurality of work stations in the apparatus; where at least one of the work stations is adapted for shutting the mouth of each bag in turn as it is presented at that station, so that the top end of each bag when the mouth is shut is upwardly facing, with the front and back panels of the bag being substantially contiguous at the top end. Means are provided for placing a closure over the upwardly facing top end, and the closure is oriented in such a manner that at least a portion of the main panel portion of the closure which is intended to contact the front panel of the bag is presented to means which applies an adhesive to that portion. Means are also provided in the apparatus for folding down the top end of the bag so that the portion of the closure to which the adhesive has been applied is brought into contact with the panel of the bag to which it is intended that the closure shall be applied; and further means are provided for maintaining contact between the closure and the front panel of the bag until such time as the adhesive bond between them is at least partially set up.
In the usual embodiment of apparatus according to the present invention, additional means are provided for forming the closure from suitable sheet plastics material.
Additionally, the present invention provides a method of applying closures of the sort discussed above to such packages as bags, by feeding a plurality of such bags, seriatim, past at least one station where the top ends of the front, back and side panels of the bag are folded; and thereafter applying the closure to the folded top end of the bag, applying adhesive to an appropriate surface of the closure, and folding the top end of the bag and closure forward so that the adhesive-coated portion of the closure is brought into contact with a portion of the front panel of the bag, and then temporarily applying pressure against the closure.
In all of the above, according to the present invention, the closure is applied to the bag after the bag has been closed and sealed by making several folds in the top ends of the front, back and side panels of the bag. This is important because the manufacturer of the product being packaged is not, therefore, reliant upon a particular supplier of bags having special closures already included -- i.e., pre-assembled -- in them; and also so that the manufacturer can use different sizes, qualities and weights of bags in the same apparatus, without having to be concerned about the width of each bag for purposes of folding a sealing strip at each side thereof. Simple adjustments may be made to apparatus according to this invention to accommodate the height of the bag being closed, and the size of the bag being closed by adjusting the machine timing.